Kelvin-Helmholtz Turbulence Associated with Collisionless Shocks in Laser Produced Plasmas

Kuramitsu, Yasuhiro; Sakawa, Y.; Dono, S.; Gregory, C. D.; Pikuz, S. A.; Loupias, B.; Kœnig, M.; Waugh, J. N.; Woolsey, N. C.; Morita, T.; Moritaka, Toseo; Sano, Takayoshi; Matsumoto, Yosuke; Mizuta, Akira; Ohnishi, Naofumi; Takabe, H.

doi:10.1103/physrevlett.108.195004

Cited by 34 publications

(37 citation statements)

References 19 publications

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“…Sheared flow settings have been traditionally studied using the MHD framework [12][13][14], where the Kelvin-Helmholtz instability (KHI) is the only instability known to develop [15]. Only very recently have collisionless unmagnetized sheared plasma flows been addressed experimentally [16] and using particle-in-cell (PIC) simulations, revealing a rich variety of electron-scale processes, such as the electron-scale KHI (ESKHI), dc magnetic field generation, and unstable transverse dynamics [17][18][19][20][21][22]. The generated fields and modified particle distributions due to these microscopic processes can strongly impact succeeding macroscopic dynamics of the sheared flow.…”

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confidence: 99%

Transverse electron-scale instability in relativistic shear flows

et al. 2015

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Electron-scale surface waves are shown to be unstable in the transverse plane of a sheared flow in an initially unmagnetized collisionless plasma, not captured by (magneto)hydrodynamics. It is found that these unstable modes have a higher growth rate than the closely related electron-scale Kelvin-Helmholtz instability in relativistic shears. Multidimensional particle-in-cell simulations verify the analytic results and further reveal the emergence of mushroomlike electron density structures in the nonlinear phase of the instability, similar to those observed in the Rayleigh Taylor instability despite the great disparity in scales and different underlying physics. This transverse electron-scale instability may play an important role in relativistic and supersonic sheared flow scenarios, which are stable at the (magneto)hydrodynamic level. Macroscopic ( c/ω pe ) fields are shown to be generated by this microscopic shear instability, which are relevant for particle acceleration, radiation emission, and to seed magnetohydrodynamic processes at long time scales. A fundamental question in plasma physics concerns the stability of a given plasma configuration. Unstable plasma configurations are ubiquitous and constitute important dissipation sites via the operation of plasma instabilities, which typically convert plasma kinetic energy into thermal and electric or magnetic field energy. Plasma instabilities can occur at microscopic (particle kinetic) and macroscopic [magnetohydrodynamic (MHD)] scales, and are generally studied separately using simplified frameworks that focus on a particular scale and neglect the other. This approach conceals the role that microscopic processes may have on the macroscopic plasma dynamics, which in many scenarios cannot be disregarded. It is now recognized, for instance, that collisionless plasma instabilities operating on the electron scale in unmagnetized plasmas, such as the Weibel [1] and streaming instabilities [2], play a crucial role in the formation of (macroscopic) collisionless shocks in astrophysical [3][4][5][6][7] and laboratory conditions [8,9]. These microscopic instabilities result from the bulk interpenetration between plasmas and are believed to be intimately connected to important questions such as particle acceleration and radiation emission in astrophysical scenarios [10,11].Sheared plasma flow configurations can host both microscopic and macroscopic instabilities simultaneously, although the former have been largely overlooked. Sheared flow settings have been traditionally studied using the MHD framework [12][13][14], where the Kelvin-Helmholtz instability (KHI) is the only instability known to develop [15]. Only very recently have collisionless unmagnetized sheared plasma flows been addressed experimentally [16] and using particle-in-cell (PIC) simulations, revealing a rich variety of electron-scale processes, such as the electron-scale KHI (ESKHI), dc magnetic field generation, and unstable transverse dynamics [17][18][19][20][21][22]. The generated fields and modif...

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confidence: 99%

Transverse electron-scale instability in relativistic shear flows

et al. 2015

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“…In order to confirm this, we have performed proton radiography to measure the shock electric/magnetic field with the LULI2000 laser facility. We have reported the experimental results of a turbulent electric field driven by KHI associated with two collisionless shock waves (Kuramitsu et al 2012). Due to the laser conditions of LULI2000, the counterstreaming plasmas are not symmetric; they can have different lateral expansions and thus transverse velocities.…”

Section: Introductionmentioning

confidence: 99%

“…Recent rapid growth of laser technologies allows us to model space and astrophysical phenomena in laboratories (Drake 1999;Remington et al 1999Remington et al , 2006Takabe et al 1999). For instance, collisionless shocks have been experimentally investigated in laser-produced counterstreaming plasmas (Morita et al 2010Kuramitsu et al 2011Kuramitsu et al , 2012Kugland et al 2012;Ross et al 2012;Fox et al 2013;Yuan et al 2013;Huntington et al 2015;Park et al 2015).W efirst reported the relatively laminar density jump with optical interferometry in collisionless counterstreaming plasmas in the absence of an external magnetic field using the Shenguang II laser facility (Morita et al 2010). In order to distinguish shock from contact surface we measured the emission jump and its time evolutions with self-emission optical pyrometry (SOP) with the Gekko XII (GXII) laser facility (Kuramitsu et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Time Evolution of Kelvin–helmholtz Vortices Associated With Collisionless Shocks in Laser-Produced Plasmas

Kuramitsu

Mizuta

Sakawa

et al. 2016

ApJ

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We report experimental results on Kelvin-Helmholtz (KH) instability and resultant vortices in laser-produced plasmas. By irradiating a double plane target with a laser beam, asymmetric counterstreaming plasmas are created. The interaction of the plasmas with different velocities and densities results in the formation of asymmetric shocks, where the shear flow exists along the contact surface and the KH instability is excited. We observe the spatial and temporal evolution of plasmas and shocks with time-resolved diagnostics over several shots. Our results clearly show the evolution of transverse fluctuations, wavelike structures, and circular features, which are interpreted as the KH instability and resultant vortices. The relevant numerical simulations demonstrate the time evolution of KH vortices and show qualitative agreement with experimental results. Shocks, and thus the contact surfaces, are ubiquitous in the universe; our experimental results show general consequences where two plasmas interact.

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“…Sorasio et al have shown a possibility of high Mach-number collisionless ES shock formation in counter-streaming plasmas in which temperatures and densities are largely different [89]. Motivated by these predictions [89,90], some authors have studied the latter scheme; the generation of collisionless ES shock in counterstreaming plasmas using double-plane target and one-directional high-energy laser systems [96][97][98][99][100][101]. Morita et al have measured a large density-jump [96], and Kuramitsu et al have shown the temporal evolution of the emission profiles [97].…”

Section: Introductionmentioning

confidence: 99%

“…In the experiments using high-energy laser systems, there are two schemes for the generation of collisionless ES shock. One is an interaction between laser-produced high-density ablating plasma and a low-density ambient plasma [94,95], and the other is an interaction between laser-ablated counter-streaming plasmas using double-plane target [96][97][98][99][100][101].…”

Section: Introductionmentioning

confidence: 99%

Collisionless electrostatic shock generation using high-energy laser systems

Sakawa

Morita

Kuramitsu

et al. 2016

Advances in Physics: X

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Collisionless shock is ubiquitous in space and astrophysical plasmas, and is believed to be a source of cosmic rays. In this review article, historical achievements of three different types of collisionless shocks, i.e. magnetohydrodynamic, electromagnetic, and electrostatic (ES) shocks, in theory/simulation, observation in space and astrophysical plasmas, and laboratory experiments are shown. An overview is given on recent progress of collisionless ES shock experiments using high-energy laser systems for two schemes. One is an interaction between laser-produced highdensity ablating plasma and a low-density ambient plasma, and the other is an interaction between laser-ablated counterstreaming plasmas using double-plane target. For the former scheme, detailed measurements of structures of collisionless ES shock and ion-acoustic soliton, and the transition from double-layer to collisionless ES shock are conducted by proton radiography. For the latter scheme, optical diagnostics are used to observe global structures of plasmas and shocks; collective laser Thomson scattering method is applied to clarify local plasma parameters, such as electron and ion temperatures, flow velocity, and electron density; and proton radiography is employed to measure a shock electric field. The measured large density-jump, steepening of self-emission profile, plasma parameters in the upand down-stream regions of a shock, and the narrow width of the shock electric field compared with the ion-ion Coulomb meanfree-path reveal the evidence for the formation of collisionless ES shock. ARTICLE HISTORY

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Kelvin-Helmholtz Turbulence Associated with Collisionless Shocks in Laser Produced Plasmas

Cited by 34 publications

References 19 publications

Transverse electron-scale instability in relativistic shear flows

Transverse electron-scale instability in relativistic shear flows

Time Evolution of Kelvin–helmholtz Vortices Associated With Collisionless Shocks in Laser-Produced Plasmas

Collisionless electrostatic shock generation using high-energy laser systems

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